This invention relates generally to a centrifugal clutch assembly, and specifically to a centrifugal clutch assembly including features for modifying a rotational speed at which the clutch assembly engages.
Typically, a centrifugal clutch assembly includes a rotating input member such as a flywheel and one or more friction disks. The friction disks are forced against pressure plates that rotate with the flywheel. Centrifugal weights are pivotally mounted to rotate radially outward against a biasing spring in response to rotation of the centrifugal clutch assembly. As the rotational speed of the centrifugal clutch assembly increases, rollers on the centrifugal weights cause clamping engagement between the pressure plates and the friction disks to transmit torque to an output shaft.
Disadvantageously, a centrifugal clutch assembly begins actuation only within a substantially fixed and limited range of engine speed. In some circumstances, it may be desirable to begin actuation of the centrifugal clutch assembly outside this limited range, such as when heavy loads are carried up an incline or when a lightly loaded vehicle is moving down an incline. It is known to vary the biasing force exerted by the biasing spring to change the point at which the clutch assembly begins actuation. Other known devices adjust a backplate position to change compressive forces exerted by the centrifugal weights relative to engine speed. However, such devices require complex and costly controls and may not adapt easily to existing driveline assemblies.
Accordingly, it is desirable to develop a centrifugal clutch assembly including simple, reliable and adaptable features for modifying the rotational speed at which the centrifugal clutch assembly engages.